Tool bracket and indexing assembly



April 8, 1952 s. P. BRUCE TOOL BRACKET AND INDEXING ASSEMBLY 2 SHEETS-SHEET 1 Filed 001;. 26, 1948 j/m rom Pin/c1:

[277E127 far April 8, 1952 s. P. BRUCE TOOL BRACKET AND INDEXING ASSEMBLY 2 SHEETSSHEET 2 Filed Oct. 26, 1948 $74 5 27 Tar Sam/020 Pin/M Patented Apr. '8, 1952 T001: BRACKET AND INDEXING ASSEMBLY Stanford P. Bruce, Detroit, Mich., assignor to Wheel Trueing Tool Company, Detroit, Mich, a corporation of Michigan Application October 26, 1948, Serial No. 56,500

Claims. (01. 12511) This invention relates to a tool bracket assembly. More particularly, the invention relates to a bracket assembly and mounting for a pawl to be used in conjunction with a ratchet wheel for automatically effecting a periodic rotation of a diamond dressing tool.

In my copending application, Serial No. 744,749, filed April 29, 1947, entitled Grinding Wheel Dressing Mechanism, I have described a mechanism for trueing the surfaces of abrasive wheels in which a tool holder is subjected to periodic rotation so that the diamond point of a diamond dressing tool is worn uniformly and presents a sharp cutting edge to th wheel at all times.

The present tool bracket is particularly suitable for use in connection with a device of the type disclosed in my aforementioned copending application, but has general applicability to pawl and ratchet assemblies.

An object of the present invention is to provide a tool bracket assembly having a pawl member capable of being adjusted into proper operating position for engaging a ratchet.

Another object of the invention is to provide a pawl assembly particularly adapted for use in conjunction with a ratchet-actuated grinding wheel dressing tool.

In general,, the tool bracket of the present invention comprises a mounting plate, an arm pivotally secured to one end of the plate, a cross member pivotally secured to both the mounting plate and the adjusting arm, a pawl pivotally attached to the cross member and a stop on the cross member for limiting the swinging arc of the pawl.

A more detailed description of the assembly of the present invention will be made in connection with the discussion of the drawings.

On the drawings:

Figure 1 is an end elevational view of a conventional grinding machine with a portion of the guard broken away and in section to show the mounting of'the tool bracket of the present invention.

Figure 2 is an end elevational view of the tool bracket of the present invention.

Figure 3 is an enlarged vertical sectional view taken substantially in the plane of the axis of the tool holder, showing the tool bracket and wheel dressing mechanism in cooperatin relationship to rotate the diamond dressing tool at an end of its traverse across the face of the grinding wheel.

Figure 4 is a fragmentary, sectional view taken substantially along the line IVIV of Figure 3,

'2 and showing in dotted lines the pawl swung in its inoperative position.

As shown on the drawings: I

In Figure 1, reference numeral l0 denotes in general a conventional grinding wheel partially shielded by means of a guard H. Behind the guard i I, a bed [2 supports a slide l3 for traversing movement parallel to the axis of rotation of the grinding wheel I 6. Associated with the slide I3 is a tool holder M which carries a diamond dressing tool l5 having a diamond point l-5a for use in trueing the grinding wheel Ill. The tool I5 is rotatable by rotation of a ratchet wheel [6 fixedly mounted with respect to the tool. The ratchet wheel i6 is actuated by engagement with a pawl- 20 which forms a part of a bracket assembly including a mounting plate ll, an adjustable arm [8, and a cross member [9.

The mounting plate I! (Figure 2) is slotted as at Ila and llb to receive bolts 36 and 31 for securing the assembly in operating position on the guard i l of the grinding wheel assembly. Attached to the mounting plate I! is an adjusting arm [8 which is composed of a slotted channel member 2! and a slide arm 22 carrying a locking screw 23 adapted to secure the slide arm 22 at any point within the length of slot 2la of channel member 2|. The adjusting arm I8 is pivotally secured to the mounting plate I! by means of a U-shaped bracket 24 which is secured to the mounting plate I! by means of rivets 25 and 26 and is secured to the adjusting arm 18 by means of an Allen type screw 27. An offset flange portion Illa (Figures 2 and 3) is formed on the cross member l9 to act as a stop to limit the swinging movement of a pawl member 20. The pawl member 20 consists of an elongated bar 21 and a ratchet-actuating member 28 secured to the bar 21 by means of rivets 29.

The pawl mechanism 20 is pivotally mounted to the cross member [9 by means of screws 4| and 42 provided with adjusting nuts 43 and M.

The pawl mechanism is thus freely swingable about the axis of screws 4| and 42, except as limitedby the stop I912.

In operation, as the slide l3 carrying the di amond dressing tool nears the end of its traverse in one direction across the face of the grinding wheel and the point 511 is out of contact with the surface of the wheel, as shown in Figure 3, the ratchet wheel i6 comes into contact with the ratchet-actuating member 28 of the pawl 20. Since the pawl 20 is held rigidly in vertical position against rotational movement in the direction of the slide by means of the stop [9a, the

ratchet wheel I6 is rotated, and with it the tool 15, through an angle equal to the angular spacing of the teeth of the ratchet wheel. Upon reversal of the direction of movement of the slide l3 to begin another traverse of the grinding wheel, the pawl 20 rides freely over the teeth of ratchet wheel I6 by virtue of its being freely pivoted from the cross member 19,, as illustrated in the dotted lines of Figure 3'. The angularity of its sloping face 28a facilitates the movement of the pawl 28 over the ratchet teeth during this reverse movement of the slide.

The tool holder 14, as best shown in Figure 3, comprises a body portion 30 having a shank.

30a. held against rotation in the assembly by means of a screw 3| engaging a notch 33b formed in the shank 30a. The body member 30 is internally bored as at 360 to rotatably' mount the pilot 32a of a tool adapter 32. A radially extending fiange adapter portion 32b formed on the tool adapter 32 is adapted to be seated against a bearing surface 30d formed in the body member 30, and is urged thereagainst by means of av collar 33 acting upon a resilient spring washer 34 and a washer 35. The tool adapter 32 which carries the diamond tool I is thus held axially under a resilient thrust that eliminates chattering while permitting rotation of the tool.

It willbe noted that whenever it becomes necessary, the pawl assembly can be adjusted to align the pawl member 20 with the ratchet wheel It. This is done by loosening screws 27, 38, 39 and screw 23 in the sliding arm 22 within the channel- 2| until the appropriate angle is achieved. and thereupon the screws 23, 21, 33 and 39- are tightened to lock the arm in its adjusted position.

A distinct advantage of the present invention lies. in the fact that the tool bracket may be disassembled for the purpose of mounting a new grinding wheel and reassembled without changing the setting of the adjusting arm 18. This is accomplished by keeping screws 23 and 38 tightened in place, and removing screws 21 and 35, thus permitting the assembly to be disassembled and reassembled without changing the angular relationship between the arm l8 and the cross member I 9.

While I have shown a particular embodiment of my invention, it will, of course, be understood that I do not wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the appended claims to cover all such modifications asfall within the true spirit and scope of my invention.

I claim as my invention:

1. A tool bracket: comprising amounting plate, an arm adjustable in length secured to one end of said plate, a cross member pivotally secured at its ends to said plate and said arm respectively, said cross member having an offset flange, portion projecting therefrom, and a pawl pivotally secured to said cross member for pivotal movement about an axis parallel to said cross member and having its pivotal movement in one direction limited by said offset. flange portion while free to move in the opposite direction.

2. A pawl assembly comprising a mounting plate, an arm adjustable in length being releasably secured to said plate, a cross member pivotally secured to both said plate and said arm, a pawl pivotally mounted on said cross member for free swinging movement thereabout, and stop means intermediate the ends of said cross member: extending into the path of swinging movement of said pawl for preventing swinging movement of said pawl in one direction.

3. A pawl assembly comprising a mounting plate, an arm of adjustable length secured thereto, a cross member pivotally secured to said mounting plate and said adjustable arm, a pawl depending from said cross member for limited swinging movement relative thereto, and stop means intermediate the ends of said cross member extending into the path of swinging movement of said pawl for preventing swinging movement of said pawl in one direction from the vertical.

4. In combination, a rotatable abrasive wheel, a guard shielding said wheel, a tool rotatable about its axis and freely extending through said guard into operative relation with said wheel, means operatively connected to said tool for reciprocating said tool to cause the same to traverse the surface of said wheel, said tool having a ratchet wheel thereon for periodically indexing said tool at the completion of a traverse of said tool across the surface of said grinding wheel, a pawl assembly arranged to rotate said ratchet wheel, said pawl assembly comprising a mounting plate secured to said guard, an arm adjustable in length removably secured to said plate, a cross member pivotally and removably secured both to said plate and to said arm, a pawl mounted for swinging movement about said cross member and positioned to engage said ratchet wheel upon the completion of a traverse of said tool across the surface of said wheel, and stop means intermediate the ends of said cross member for limiting the arc through which said pawl may be swung.

5. In a grinding wheel dressing assembly having a rotatable abrasive wheel, a guard shielding said wheel, a dressing tool rotatable about its axis and freely extending through said guard into operative relation with said wheel, means operatively connected to said tool for reciprocating said tool to cause the same to traverse the surface of said wheel, said tool having a ratchet wheel thereon for periodically indexing said tool at the completion of its traverse across the surface of said grinding wheel, a pawl assembly adapted to rotate said ratchet wheel, said pawl assembly comprising a mounting plate secured to said guard, an arm adjustable in length pivotally and removably secured to said plate, a cross member pivotally and removably secured to both said plate and said guard, a pawl mounted for free swinging movement about said cross member and positioned to engage said ratchet wheel at the completion of a traverse of said tool across the surface of said abrasive wheel, and an offset flange on said cross member for limiting the are through which said pawl may be swung.

STANFORD P. BRUCE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 159,124 Tomlinscn Jan. 26, 1875 248,883 Ralston Nov. 1, 1881 1,858,212 Soule May 10, 1932 1,968,030 Filippis July 31, 1934 2,055,291 Henry .Sept. 22, 1936 2,072,995 Wilcox Mar. 9, 1937 2,189,344- Gustafson- Feb. 6, 1940 2,281,224 Baum'gartnen an Apr. 28,- 1-942 

